Abrasive particles and abrasive articles made using them are useful for abrading, finishing, or grinding a wide variety of materials and surfaces in the manufacturing of goods. As such, there continues to be a need for improving the cost, performance, or life of the abrasive particles and abrasive articles in which they are incorporated.
Shaped abrasive particles and especially ceramic shaped abrasive particles (e.g., made of alpha alumina) have revolutionized the abrasives industry over the past 10 years or so. Shaped abrasive particles have non-random shapes imparted by the way in which they are made. Shaped abrasive particles, in general, can have superior performance as compared to randomly crushed abrasive particles. By controlling the shape of the abrasive particle it is possible to control the resulting performance of abrasive articles in which they are incorporated.
According to one common method, described in U.S. Pat. Appln. Publ. No. 2011/0146867 A1 (Boden et al.) alpha alumina shaped abrasive particles having grooves can be made from a dispersion of aluminum oxide monohydrate that is gelled, molded to shape, dried to retain the shape, calcined, and then sintered.
It is known that grinding stainless steel material is more challenging than carbon steel. In fact, in coated abrasive articles, materials that are targeted for finishing stainless steel are generally provided with a top layer known as a supersize layer (or simply a “supersize”). Such a supersize layer is generally highly filled with halogen-containing particulates (e.g., KBF4 and/or Na3AlF6 (cryolite)), also known as grinding aids, that enhance the abrading (e.g., grinding) performance of the abrasive. However, halogens are generally regarded as contaminants in stainless steel, and especially in the nuclear industry. The presence of halogens is also known to promote stress corrosion cracking in austenitic welds such as, for example, 304 stainless steel and nickel-based alloy welds.